Integrated method for producing a fuel component from biomass and system therefor

ABSTRACT

Disclosed here are integrated methods and systems for producing fuel from biomass. The methods and systems pertain to gasifying a feed derived from biomass fermentate separation residue, such as corn-based distiller&#39;s grains, and producing a liquid transportation fuel component, such as aviation turbine fuel, from the gasified feed in a hydrocarbon synthesis reactor. At least a portion of the waste heat from the hydrocarbon synthesis reactor is supplied to a thermal process for liquefying, fermenting or distilling a biomass, or to a thermal process for separating or treating a biomass fermentate separation residue.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional utility application claimingpriority under 35 U.S.C. 119(e) of prior-filed copending provisionalapplication Ser. No. 60/953,364, filed 1, Aug. 2007, entitled “MethodsFor Converting Biomass Into Transportation Fuel By IntegratingGasification And Fischer-Tropsch Conversion Systems Into ExistingEthanol Plants”, which is hereby incorporated by reference in itsentirety.

BACKGROUND

The present disclosure generally relates to integrated methods andsystems for converting biomass into fuels. In particular, someembodiments herein relate to integrated methods for convertingcorn-based biomass into aviation jet fuel.

The United States imports over 60% of its transportation fuel. Anysignificant disruption overseas could result in significant deleteriouseffects to the current transportation capabilities and economy of theUnited States and elsewhere. Moreover, conventional transportation fuelshave become associated with an undesirable elevation in greenhouse gasemissions, which are thought to contribute to global climate change. Inan effort to address both of these unwanted situations, researchers havebegun turning to alternative fuel sources, including biofuels, toreplace the fossil-fuel derived products used today.

Biofuel can be broadly defined as solid, liquid, or gas fuel consistingof, or derived from, biomass. Biomass is any material derived fromrecently living organisms, including plants, animals and the byproductsthereof, and is a renewable energy source based on the carbon cycle.Some examples of agricultural products that can be specifically grownfor biofuel production include corn, soybeans, rapeseed, wheat and sugarcane. Biofuel is considered an important means of reducing greenhousegas emissions, as well as increasing energy security by providing aviable alternative to currently used fossil fuels.

Currently, corn (or other biomass) can be used to manufacture ethanol,which itself is a burgeoning transportation fuel. Ethanol plants can usecorn (or other biomass) to produce ethanol, but usually also producelarge quantities of biomass fermentate distillation residues, such asdistiller's grain, as a byproduct of the fermentation and distillationprocess. However, as the number of ethanol plants continues to multiply,the market for biomass fermentate distillation residues such asdistiller's grain becomes increasingly saturated, resulting in a steadydecline in prices and threatening an important revenue stream forethanol plant owners.

Accordingly, there remains a need for methods for manufacturingtransportation fuel that not only addresses the security and greenhousegas issues set forth previously, but that also provides support to theethanol industry as a fossil-fuel alternative.

BRIEF SUMMARY OF THE INVENTION

One embodiment of the present invention is directed to an integratedmethod for producing fuel from biomass, which method comprises the stepsof (a) providing a feed comprising biomass fermentate separationresidue; (b) gasifying feed from step (a) in a gasification reactor toproduce a mixture comprising CO and H₂; (c) contacting the mixturecomprising CO and H₂ with a hydrocarbon synthesis catalyst in asynthesis reactor to produce heat and an effluent comprising a liquidtransportation fuel component; and (d) supplying at least a portion ofthe heat to at least one thermal process selected from the groupconsisting of biomass liquefaction, fermentation, fermentation productdistillation, dehydrating agent regeneration, fermentate separationresidue concentrating, and fermentate separation residue drying.

A further embodiment of the present invention is directed to anintegrated method for producing a turbine fuel from corn-based biomass,the method comprising the steps of: (a) providing a feed comprisingcorn-based biomass fermentate distillation residue; (b) gasifying feedfrom step (a) in a gasification reactor to produce a mixture comprisingCO and H₂; (c) contacting the mixture comprising CO and H₂ with ahydrocarbon synthesis catalyst in a synthesis reactor to produce heatand an effluent comprising a liquid turbine fuel component; and (d)supplying at least a portion of the heat to at least three thermalprocesses selected from the group consisting of corn liquefaction, cornmash fermentation, corn fermentation product distillation, corn-basedethanol dehydrating agent regeneration, corn mash fermentatedistillation residue concentrating, and corn mash fermentatedistillation residue drying.

A yet further embodiment of the present invention is directed to anintegrated system for producing fuel from biomass, the systemcomprising, (a) a unit configured to provide a feed comprising biomassfermentate separation residue; (b) a gasification reactor for gasifyingfeed from unit (a) to produce a mixture comprising CO and H₂, (c)catalytic hydrocarbon synthesis zone configured to react the mixturecomprising CO and H₂ to produce heat and an effluent comprising a liquidtransportation fuel component; and (d) at least one heat supply conduitconfigured to supply at least a portion of said heat to at least onethermal process selected from the group consisting of biomassliquefaction, fermentation, fermentation product distillation,dehydrating agent regeneration, fermentate separation residueconcentrating, and fermentate separation residue drying.

Other features and advantages of this invention will be betterappreciated from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block flow diagram schematically setting forth methods inaccordance with embodiments of the invention.

FIG. 2 is an illustrative and schematic flow-chart of a method forproducing corn-based distiller's grains, in accordance with embodimentsof the invention.

FIG. 3 is a schematic diagram of a mode of removing heat from ahydrocarbon synthesis reactor, in accordance with embodiments of theinvention.

FIG. 4 is a block flow diagram, schematically setting forth variantmethods in accordance with other embodiments of the invention.

DETAILED DESCRIPTION

As noted, an embodiment of the present invention is directed to anintegrated method and system for producing fuel from biomass. Inparticular, the method and systems described herein enable the efficientand effective utilization of waste heat from hydrocarbon synthesis ofliquid transportation fuel components, in various thermal processes.

Referring now to FIG. 1, is shown a block flow diagram, schematicallysetting forth methods in accordance with embodiments of the invention. Abiomass fermentate separation residue 10 is supplied to a step ofproviding 100 a feed comprising the biomass fermentate separationresidue 10. As will be described in more detail later in thisdisclosure, the step of “providing” 100 may comprise a pretreatment stepsuch as pyrolysis, catalytic conversion, drying, concentrating, and/orcharring (not specifically shown here). Provided feed 11 comprisingbiomass fermentate separation residue is recovered from providing step100. The provided feed 11 is then supplied to a gasifying step 101 in agasification reactor, to produce a mixture 12 comprising CO and H₂. Thismixture 12 may be supplied (either directly or indirectly) to acontacting step 102 wherein the mixture 12 is contacted with ahydrocarbon synthesis catalyst in a synthesis reactor to produce heat 14and an effluent 13 comprising a liquid transportation fuel component.

Heat 14 may be supplied to any one or more of six thermal processes 109,shown collectively in a dotted box. The six thermal processes arebiomass liquefaction 103, fermentation 104, fermentation productdistillation 105, dehydrating agent regeneration 106, fermentateseparation residue concentrating 107, and fermentate separation residuedrying 108.

As used herein, the term “biomass” is broadly defined as generallyincluding materials derived from plants, such as woody materials, forestresidues, agricultural residues, or crops; or the like. Thus, thebiomass as used herein includes materials that are formed as a result ofphotosynthesis. This is significant for the production of liquidtransportation fuel components that are to be considered“carbon-neutral” or even “carbon-negative”, in the context ofcarbon-containing fuels as suspected climate-change agents.

The woody materials and forest residues may include wood, woodchips, sawdust, bark or other such products from trees, straw, grass, and thelike. Agricultural residue and crops may further include short rotationherbaceous species, husks such as rice husk, coffee husk, etc., maize(i.e., corn), wheat, corn stover, oilseeds, residues of oilseedextraction, other grains, and the like. The oilseeds may be typical oilbearing seeds like soybean, camolina, canola, rapeseed, corn,cottonseed, sunflower, safflower, olive, peanut, and the like. Biomassmay also include material obtained from agro-processing industries suchas the oil industry, e.g., a deoiled residue after extraction of oilfrom the oil seeds. Biomass may also include other tree-based productssuch as shells, e.g., coconut shell, almond shell, walnut shell,sunflower shell, and the like. Cellulosic fibers like coconut, jute, andthe like, may also constitute all or part of biomass. The biomass mayalso include algae, microalgae, and the like. It could also includeagro-products after preliminary processing. As an example, this mightinclude feedstocks such as bagasse (obtained after juice removal fromsugarcane), cotton gin trash, and the like.

Methods in accordance with embodiments comprise a step of providing afeed comprising biomass fermentate separation residue. Such residues canbe those produced as a by-product of the separation (e.g., distillation)of biomass fermentation into components. Tile biomass which is fermentedis typically one or more plant biomass selected from woody materials,forest residues, agricultural residues, crops, and the like. Typically,biomass can fermented microbially to produce chemicals such as alcoholsand other organic chemicals. Fermentation-derived alcohols can includebutanol and ethanol, and other (usually volatile) organic chemicals caninclude ketones, carboxylic acids, aldehydes, and the like. Thesechemicals are desirable products of the biomass fermentation process,but must be separated out from tile fermentate. In general, a typicalmethod of separating a desirable volatile product such as ethanol from abiomass fermentate can involve the distillation of the fermentate.However, other separation methods such as pervaporation or membraneseparation can also be employed to recover the desired volatile organicproduct from the fermentate. The portion which is rejected from theseparation process when is the “biomass fermentate separation residue”;it is this latter material which is employed in methods according toembodiments of the invention.

Fermentation processes in accordance with embodiments of the presentinvention usually involve microbial (e.g., yeast-mediated or bacterial)conversion of a biomass-derived feedstock. In one illustrative (butnon-limiting) embodiment, corn can be fermented to produce a fermentatecomprising ethanol. In a typical ethanol production process utilizingcorn as the feedstock, the corn may be firstly ground to produce amilled corn. The milling can be either dry milling or wet milling. Themeal can then be mixed with water and an enzyme, such as alpha-amylase,and then passed to cookers to liquefy starch into a mash. Heat may thenbe applied at this stage to enhance liquefaction. In some embodiments,cooking to a temperature as high as 150° C. may be employed. In somefurther typical embodiments, the mash from the cookers may be cooled anda secondary enzyme, such as glucoamylase, can be added to convert theliquefied starch to fermentable sugars. Yeast can then be added to themash to ferment the sugars to ethanol and carbon dioxide. One or morefermenters can be used.

The fermented mash, now called beer, generally contains about 10%ethanol but additionally may contain non-fermentable solids from thecorn and yeast cells. Fermented mash can then be transferred to adistillation system to remove ethanol from the solids and the water. Thealcohol is typically collected from the distillation system atazeotropic (usually about 95%) concentration, and the distillationresidue (sometimes called stillage) is also collected. Once distillationresidue is dried and/or concentrated, it is then termed distiller'sgrain. As noted, one exemplary embodiment of a biomass fermentateseparation residue is distiller's grain.

Referring now to FIG. 2, here is shown an illustrative and schematicflow-chart of a method for producing one form of biomass fermentateseparation residue, namely, corn-based distiller's grains. Corn issupplied through 15 and is fine milled in 200 to expose its starch.Milled corn is supplied though 16 to cooker 201, to which is addedenzymes (not specifically shown) and heat via steam line 17. Cooker 201is an example of a thermal process which may employ heat recovered fromthe hydrocarbon synthesis reactor. Cooked corn is sent through line 18to fermenter 202, to which is also supplied yeast through 19 and enzymesthrough 20. The fermented corn mash (“fermentate”) is supplied via 21 todistillation apparatus 203. Steam is supplied through 22 to drivedistillation of the corn mash. From the overhead of distillationapparatus 203 is collected azeotropic ethanol through 23. Thisazeotropic ethanol is then passed to an active bed 205 of dehydratingagent, to produce substantially anhydrous ethanol via 27. A spent bed206 of dehydrating agent, which is offline from dehydrating duty, isregenerated by passage of an optionally heated inert gas through 28, todrive off water in 29.

From the bottoms of distillation apparatus 203 is collected corn-basedstillage, which is sent via line 24 to a processor 204, wherein thestillage is processed through a centrifuge and heated dryer to removeliquids. Heat is indirectly supplied through line 25 (in the form of hotgas) and dried distiller's grains are collected via line 26.

There are various grades of distiller's grains recovered as corn-baseddistillation residue, including distiller's wet grains (DWG),distiller's dry grains (DDG), dried distiller's grains with solubles(DDGS), and corn-based grain stillage syrup. Typically, DWG containsgreater than about 65% moisture, and DDG often contains from about 10%to about 50% moisture. Stillage syrup usually has from about 20 to about40% solids. It has been found that these and other biomass fermentateseparation residues offer advantages when forming liquid transportationfuel components according to embodiment of the invention, since suchresidues have idea H/C ratios, e.g., usually around 2:1.

In accordance with embodiments of the invention, a feed comprisingbiomass fermentate separation residue is provided to gasificationreactor; such gasification reactor (also referred to as a gasifier) willbe described in greater detail hereinunder. In some embodiments, thestep of “providing” a feed may comprise a treatment step performed uponthe biomass fermentate separation residue, prior to its being fed to agasification reactor. Such a treatment step may be selected from one ormore of pyrolysis, catalytic conversion, drying, concentrating, andcharring; and the like. Each of these treatment steps may be capable ofrendering biomass fermentate separation residue into a state moresuitable for gasification. For instance, owing to a relatively highmoisture content, a biomass fermentate separation residue such as DWGshould be dried and/or concentrated prior to being fed to a gasifier, soas to enhance the efficiency of the reactor and avoid agglomeration orother deleterious effects of the moisture. In other embodiments, it maybe advantageous to pyrolyze biomass fermentate separation residue in thesubstantial absence of oxygen, in order to convert at least a portion ofthe residue to a bio-oil or a char, either of which can then fed to agasifier. In yet further embodiments, a catalytic conversion of biomassfermentate separation residue may be performed, to convert the residueto a form more suitable for gasification (e.g., more solids and/orhigher carbon content and/or less tarry character).

In some other embodiments, the step of “providing” a feed comprising abiomass fermentate separation residue may simply comprise conveying orfeeding a biomass fermentate separation residue to a gasifier, withoutany of the treatment steps noted above. Regardless of the nature of howthe feed comprising a biomass fermentate separation residue is provided,the present disclosure also encompasses embodiments where the biomassfermentate separation residue is combined with a supplemental feedmember, such as another biomass-based material (e.g., corn stover)and/or carbonaceous fuel. In certain cases, biomass fermentateseparation residue is combined or mixed with at least one supplementalfeed member selected from low rank coal, liquid hydrocarbonaceous fuel,coke, oil shale, tar sands, asphalt, pitch, another biomass-basedmaterial, and mixtures thereof, and the like. The combining or mixingmay occur within a gasifier, or more usually, prior to being fed to agasifier.

It may be especially advantageous to employ low rank coals as thesupplemental feed member to be combined with biomass fermentateseparation residue. Coals having a “low rank” are generally understoodby persons skilled in the art to typically be those coals having a lowergrade than bituminous, e.g., sub-bituminous or lignitic coal. In somecase, such low rank coals may have a relatively high oxygen content,such as from about 16% to 25% by weight. Other characteristics of lowrank coals may include a relatively high moisture content, such as inthe range of about 10% to 40%, and a relatively high dry ash content,such as in the range of about 12% to 40%. Low rank coals are present inabundance in tie mid-continenit region of the United States (as PowderRiver Basin coal), and in China (as brown coal).

Where a supplemental feed member is employed, the biomass fermentateseparation residue may be directly combined therewith, or one or more ofthe aforementioned treatment steps (e.g., pyrolysis, catalyticconversion, drying, concentrating, charring) is performed upon a biomassfermentate separation residue prior to mixing with the supplemental feedmember.

Regardless of how the feed is obtained or prepared, (e.g., whether ornot biomass fermentate separation residue is mixed with a supplementalfeed member and/or is pretreated in a treatment step), the feed isgasified in a gasification reactor to produce a mixture comprising atleast carbon monoxide and hydrogen. As is generally known, the termgasification refers to a process which converts carbonaceous and/orhydrocarbon feedstocks into a synthesis gas (also known as syngas)comprising hydrogen and carbon monoxide. In a typical gasificationplant, (1) a carbonaceous feedstock arid (2) air, oxygen, steam, waterand/or CO₂; are contacted within a gasification reactor, where partialoxidation of the feedstock occurs. The feedstock and molecular oxygenreact and form syngas. Non-gasifiable ash material and unconvertedand/or incompletely converted feedstock are by-products of the process.In some case, a quench process is used to cool and saturate the syngas.

In accordance with embodiments of the invention, a gasification reactormay suitably be one or more type, such as fixed bed, bubbling bed,fluidized bed, entrained flow gasifier; or the like. Furthermore, thegasification reactor may have at least one characteristic selected fromslurry-fed, pressurized, slagging; or the like. For example, in anentrained flow gasifier, gasifying agents such as oxygen, air, steam, orcombination of these, are used to fluidize the feedstock and carry it atleast some distance through the gasification reactor. Each of thesetypes of gasification reactors and operating modes are per se known foruse in generating syngas from coal, for instance.

In some embodiments, the gasification reactor can be operated in apressurized mode (which can be any pressure above atmospheric but istypically between about 10 bar and about 40 bar); which may in certaincases afford good overall efficiencies. In some embodiments, thegasification reactor may instead be operated at substantiallyatmospheric pressure. In certain embodiments, one may operate thegasification reactors at temperatures higher than about 1000° C., e.g.,from about 1000° C. to about 1400° C., to more effectively gasify tarrycomponents of the feed. However, operation at such high temperaturescould require use of expensive refractory materials in the gasificationreactor. In yet another embodiment the gasification reactor is operatedat moderate temperatures, typically from about 700° C. to about 1000° C.

Although step (a) through (d) are noted as process steps for the presentintegrated method for producing fuel from biomass, this is not to betaken to exclude the presence or use of other steps, to be describedhereinunder. For instance, the mixture of CO and hydrogen generated inthe gasification reactor in step (b) may also undergo further treatmentsteps such as scrubbing to remove acidic gases; or water-gas shifting toadjust the CO/hydrogen ratio. A step of adjusting the CO/H₂ ratio in amixture can be accomplished by an adjusting step selected from one ormore of: selective removal of CO, selective removal of hydrogen,water-gas shift, reverse-water-gas-shift; or the like. In cases whereselective removal of CO or selective removal of hydrogen is desired, itmay be performed by selective oxidation or by membrane processing.Adjusting the CO/H₂ ratio in the mixture may promote the formation ofdesired products in the effluent of the hydrocarbon synthesis reactor,as explained in further detail below.

According to embodiments of the invention, it is typical that rawproduct syngas from gasification reactors further comprises othergaseous components as impurities in addition to CO and hydrogen. Theseimpurities may include CO₂, NH₃, H₂S, HCN, HCl, COS, nitrogen, mercury,and the like. Such other gaseous components may be deleterious todownstream processing steps (e.g., hydrocarbon synthesis) performed uponthe mixture, or may lessen the efficiency of these downstream processingsteps. Therefore, in some embodiments, methods of the present disclosurefurther comprise an additional step of scrubbing or otherwise at leastpartially removing at least one impurity selected from ammonia, carbondioxide, hydrogen sulfide, HCl, hydrogen cyanide, mercury, nitrogen andcarbonyl sulfide from the mixture comprising CO and H₂ prior tocontacting the mixture with the hydrocarbon synthesis catalyst.Scrubbers may be suitably employed for the acidic gaseous impurities(e.g., CO₂ and H₂S), while guard beds may be used for mercury removal.In embodiments where carbon dioxide is separated and recovered from theraw product syngas, carbon dioxide may in certain cases be sequesteredso as to limit emission of climate-change suspect compounds.

In embodiments of the invention, a gaseous mixture comprising CO and H₂(suitably scrubbed of impurities and adjusted in CO/H₂ ratio, asappropriate), is passed to a synthesis reactor in which contact is madewith a hydrocarbon synthesis catalyst, to produce heat and an effluentcomprising a liquid transportation fuel component. Such a hydrocarbonsynthesis catalyst may comprise any of the catalytic materialsheretofore known for hydrocarbon synthesis by the Fischer-Tropsch (F-T)reaction, such as at least one selected from Fe, Co, Ni, Re, Ru; and thelike. These catalytic materials may be provided in elemental and/orcompound form. Typically, these catalytic materials may be provided andused in dispersed form and supported upon an inorganic support material,such as a refractory inorganic support material, e.g., zirconia,titania, or alumina. Often, the catalytic materials of the hydrocarbonsynthesis catalyst of the present embodiments further comprises one ormore promoter material. In some embodiments, the hydrocarbon synthesiscatalyst comprises one or more of Fe, Co, Ni, Re, Ru present in anamount of from about 1% to about 50% by weight of total hydrocarbonsynthesis catalyst. Where the hydrocarbon synthesis catalyst comprisesat least one selected from Fe, Co, Ni, Re, Ru, then any one or more ofthe following may be employed as co-catalysts or promoters: Re, Ru, Pt,Fe, Ni, Th, Zr, Hf, U, Mg and La; and the like. Often, use of Co ascatalyst material promotes the formation of paraffins.

In embodiments of the invention, a gaseous mixture comprising CO and H₂is contacted with a hydrocarbon synthesis catalyst under conditions oftemperature such as between about 140° C. to about 400° C. (or morenarrowly, between about 200° C. to about 250° C.); and at conditions ofpressure such as between about 0.5 to about 50 bars (or more narrowly,between about 2 to about 25 bars). Note that here (as elsewhere in thisdisclosure), all ranges disclosed are inclusive of the recited endpointand are independently combinable.

The hydrocarbon synthesis reactor may be one or more of a variety ofreactor types; for example, fixed bed reactors containing one or morecatalyst beds, slurry reactors, fluidized bed reactors, or a combinationof different type reactors. In some embodiments, the hydrocarbonsynthesis process is a slurry Fischer-Tropsch process, in which a syngascomprising a mixture of H₂ and CO is bubbled up through a slurry in areactor which comprises a particulate hydrocarbon synthesis catalystdispersed and suspended in a slurry liquid comprising hydrocarbonproducts of the synthesis reaction which are liquid at the reactionconditions.

In accordance with some embodiments of the invention, the contact ofsyngas with the hydrocarbon synthesis catalyst in the synthesis reactorresults in an effluent comprising one or more liquid transportation fuelcomponent. Such a “liquid transportation fuel component” (which usuallycomprises at least paraffins) may itself be used as a liquidtransportation fuel, or may be suitably blended with another fuel and/oradditive to be useful as a liquid transportation fuel. Therefore, theterm “component” is employed to signify that the effluent from thesynthesis reactor may be used as part of a liquid transportation fuel,or as a fuel itself (after any appropriate separation and/orhydroprocessing, as explained more fully below). For instance, incertain embodiments, methods and systems herein provide a liquidtransportation fuel component that has sufficient lubricity and otherparameters such that it can be used as a jet turbine fuel. Inalternative embodiments, liquid transportation fuel components requireadmixture with other fuels and/or additives in order to be useful as ajet turbine fuel. As used herein a “liquid transportation fuel” and a“liquid transportation fuel component” generally refers tohydrocarbonaceous fuels boiling within the range of gasoline, jet fuel,kerosene, or diesel. In some embodiments, the liquid transportation fuelcomponent may be used as a turbine fuel. The formation of a desired typeof liquid transportation fuel component may be promoted by: (1) choosingthe proper chemical composition for the feed comprising biomassfermentate separation residue; (2) adjusting the CO/H₂ ratio of thesyngas formed in the gasification reactor; (3) adjusting conditionsincluding temperature, pressure, and/or catalyst in the hydrocarbonsynthesis reactor; and (4) combinations of the foregoing. For instance,the H/C ratio in dried distiller's grains may be ideal for conversioninto (e.g., paraffinic) liquid transportation fuel components.

A “turbine fuel” refers to a fuel composition which may be burned in aturbine to provide power. Turbines may be stationary, such as those usedto generate electricity, or they may be used to power mobile platforms,such as providing power for ships or airplanes. Turbine fuels meetingcertain specifications may be used as jet fuel for airplanes.Specifications for turbine fuel intended for use in jet engines are morestringent than those for fuels intended for use in turbines used toproduce electricity.

As is generally known, a “jet fuel” is a material suitable for use inaviation turbines and typically meets the current version of at leastone of the following specifications: ASTM D1655; DEF STAN 91-91/3 (DERD2494); International Air Transportation Association (IATA) “GuidanceMaterial for Aviation Turbine Fuels Specifications”, 4th edition, March2000; United States military jet fuel specifications MIL-DTL-5624; andMIL-DTL-83133, and variants thereof. Also known as aviation turbinefuel, jet fuel is an aviation fuel with various specified grades such asJet-A, JP-A, JP-B, JP-4, JP-5, JP-7, JP-8, JP8+100, and the like. Jetfuel is a special grade of kerosene; the specifications of variousgrades are specified by various standards. As an example, JP-8 isdefined by standard MIL-T-83133C.

Where the liquid transportation fuel component according to embodimentsof the invention is to be used for aviation turbine or jet fuelpurposes, it generally meets one or more of the following parameters: anH/C ratio of greater than about 1.85, more narrowly, between about 1.85and about 2.20; a flash point of at least about 38° C., more narrowly,from about 38° C. to about 60° C., and even more narrowly from about 40°C. to about 60° C.; and a freeze point of less than about −40° C., morenarrowly less than about −47° C., often having an average freeze pointof from about −50° C. to about −60° C. (freeze point as defined byASTM-D-2386). In some embodiments of the invention, the liquidtransportation fuel component additionally meets one or more of the jetfuel standard specifications noted previously.

In some embodiments, various additives such as antioxidants, antistaticagents, corrosion inhibitors, icing inhibitors, etc., may be added tothe liquid transportation fuel component, before it is used intransportation, e.g., before it is used as jet fuel or aviation turbinefuel. The amount and type of additives may be different for differentgrades of transportation fuel.

In accordance with some other embodiments of the invention, the contactof syngas with the hydrocarbon synthesis catalyst in the synthesisreactor results in an effluent comprising one or more liquidtransportation fuel component, where the liquid transportation fuelcomponent is thereafter upgraded by hydroprocessing. This additionalhydroprocessing, step is generally selected from one or more ofhydrocracking, hydrotreating, and isomerization; and the like. Suchhydroprocessing steps per se are generally known to persons of skill inthe art of hydrocarbon processing. Hydroprocessing may usually becarried out in the presence of free hydrogen, for removal of alcoholsand hydrogenation of olefins present in the effluent. In some cases,upgrading by hydroprocessing may be performed upon some or all of theliquid transportation fuel component, in order to impart desiredproperties. For instance, a liquid transportation fuel component inaccordance with some embodiments of the present invention, can beupgraded by hydroprocessing to be suitable for use as aviation turbinefuel.

In still further embodiments of the invention, the effluent from thehydrocarbon synthesis reactor comprising one or more liquidtransportation fuel component may be separated by one or moredistillation or other separation process. Usually, such distillation orseparation will be on the basis of boiling point. Thus, the effluentcomprising one or more liquid transportation fuel component may bedistilled into one or more lower boiling fractions and one or morehigher boiling fractions. It may be advantageous to perform suchdistillation to separate liquid fuel components from waxy fuelcomponents. Finally, both distillation and hydroprocessing, in anyorder, may be performed upon effluent from the hydrocarbon synthesisreactor.

As previously noted, integrated methods according to embodiments of theinvention, comprise supplying at least a portion of heat produced by thehydrocarbon synthesis step to at least one thermal process whichrequires heat, selected from biomass liquefaction, fermentation,fermentation product distillation, dehydrating agent regeneration,fermentate separation residue concentrating, and fermentate separationresidue drying. More particularly, the heat produced by the hydrocarbonsynthesis step is supplied to at least two, or at least three, or atleast four, or at least five, of said thermal processes. Although eachof these processes which require heat is denoted as a “thermal process”,this is not to indicate that only thermal or physical processes occur;each of these processes may also additionally comprise chemical and/orbiochemical process. For instance, a biomass liquefaction process can bea ground corn cooking process whereby corn meal is heated in thepresence of moisture and an enzyme. Furthermore, although some of thesteps of the methods may be parallel to other steps of the method, theterm “integrated,” as used herein, means that certain steps of themethod are interrelated or dependent upon either earlier or later stepsof the total method.

The heat which emanates from the synthesis reactor (e.g.,Fischer-Tropsch reactor) may be recovered in many suitable ways,including heat recovery by indirect heat exchange with the synthesisreactor, either internal to the reactor or externally, or by heatrecovery from the hot effluent gases removed as product from thereactor. In typical hydrocarbon synthesis reactors, a stream can beremoved (e.g., the overhead stream) that comprises water, among othercomponents. Heat may be obtained from the hydrocarbon synthesis reactorsby cooling the water-containing stream from the reactor, or by coolingthe reactor itself, or by cooling other effluent streams from thereactor. More specifically, one or more hot effluent stream from thehydrocarbon synthesis reactor may be passed through a heat exchanger. Ausable heat exchanger can be a shell and tube heat exchanger or a weldedplate and frame heat exchanger. Alternatively, the synthesis reactor maycontain cooling coils, which serve to remove heat generated during thehighly exothermic Fischer-Tropsch reaction. Both cooling coils internalto the hydrocarbon synthesis reactor, and heat exchangers for heatremoval from hot effluent streams, can be used simultaneously.

In order to supply the heat from the hydrocarbon synthesis reactor tothe thermal processes which require heat, one may suitably employconventional means. Use of heat transfer fluids such as steam or heatedair or other heated gas are well known and effective means for supplyingrecovered heat to where it is required.

Referring now to FIG. 3, here is shown a schematic diagram of anexemplary (but non-limiting) mode of removing heat from a hydrocarbonsynthesis reactor and supplying it to one or more thermal processes.Fischer-Tropsch reactor 300 is fed with a syngas through line 30, and aneffluent comprising a liquid transportation fuel component is recoveredthrough 31. Cooling water in line 32 is fed through cooling coils withinreactor 300 to make indirect heat contact with the hot reactor, and thesteam raised by this process is supplied to drive the one or morethermal processes 109.

Thermal processes which requires heat are selected from one or more ofbiomass liquefaction, fermentation, fermentation product distillation,dehydrating agent regeneration, fermentate separation residueconcentrating, and fermentate separation residue drying. The integratedsystems and methods disclosed herein may obviate or reduce the necessityto import energy to drive these thermal processes. For example,fermentate separation residue drying (e.g., drying distiller's grains)has been typically performed using natural gas fired burners in theprior art. This can increase costs for producing ethanol from corn.However, the present methods and systems may offer the advantage of costsavings by recycling a form of waste heat.

A biomass liquefaction process may comprise enzymatic and/or bacterialdecomposition of any of the biomass materials noted previously. Anexemplary but non-limiting type of biomass liquefaction may be thepreviously-described process where milled corn is mixed with water andan enzyme, and then passed to cookers to liquefy starch into a mash.Heat is usually required to enhance liquefaction.

A fermentation process may comprise enzymatic, bacterial, and/oryeast-mediated production of an alcohol from a biomass material. Anexemplary but non-limiting type of fermentation process can include thepreviously-described process for recovery of ethanol from corn mashfermentation. Fermentation processes benefit from heat input.

A fermentation product distillation process typically comprisesdistillation of a fermentate to separate an alcohol. One non-limitingexample of a fermentation product distillation process is thedistillation of fermented corn mash to recover ethanol as a fermentationproduct. A fermentation product distillation process usually requiresheat to drive the production of the desired alcohol, e.g., azeotropicethanol.

A dehydrating agent regeneration process generally comprisesregeneration of a spent solid dehydrating agent. Usually, such a spentsolid dehydrating agent has been used to dehydrate a biomassfermentation product (e.g., ethanol from corn fermentation). The mostaccepted approach to dehydration of ethanol now used industrially is touse adsorption by molecular sieves as solid dehydrating agent, such aszeolite 3A. Typically a two bed system is used in which one bed of soliddehydrating agent receives a flow of azeotropic ethanol for dehydrationand the other undergoes regeneration. Although in some instancesregeneration of a bed containing spent solid dehydrating agent can occurunder vacuum, in other cases heat can be used to drive off the waterfrom the spent dehydrating agent and thus regenerate the agent.

A fermentate separation residue concentrating process generallycomprises reducing the volume of a fermentate separation residue. A“fermentate separation residue” can be the rejected residue afterseparation (e.g., distillation) of a desired product (e.g., an alcoholor other volatile organic compound) from a biomass (e.g., corn)fermentate. Such fermentate separation residue may include corn-baseddistiller's grains or distiller's syrup. Reduction in volume may beperformed in a centrifuge. Heat may sometimes be employed to aid involume reduction.

A fermentate separation residue drying process may include removing atleast some moisture from a fermentate separation residue, such as dryingcorn-based distiller's grains in a dryer (e.g., a steam tube rotary orring dryer). Often, for particular purposes, such residues requiredrying to a given moisture level prior to further utilization, e.g.,prior to gasification or use as feed. In such cases, drying can beaccomplished using conventional means, such as steam dryer, gas dryer,spray dryer, pneumatic conveying dryer, fluidized bed dryers, rotarykilns, or the like.

In some particular embodiments, the thermal process is used to generate,separate and/or treat the biomass fermentate separation residue; or thethermal process is used to treat another product of the same processwhich generates, separates and/or treats the biomass fermentateseparation residue. Stated in other words: the thermal process to whichheat is supplied may be a process that concentrates or dries the biomassfermentate separation residue that is sent to the “providing” step (a).For example, this would be the case where dried distiller's grains areconverted into liquid transportation fuels, and the heat fromhydrocarbon synthesis is used to dry these distiller's grains.

Alternatively, the thermal process may be a process that liquefies,ferments, or distills the biomass from which the biomass fermentateseparation residue is derived. For example, this would be the case whereheat from hydrocarbon synthesis from syngas is used to ferment, liquefy,or distill corn to make the distiller's grains which are gasified tomake the syngas.

Alternatively, the thermal process may be one which treats anotherproduct of the same process which generates, separates and/or treats thebiomass fermentate separation residue. For example, this would occurwhen heat from hydrocarbon synthesis is used to regenerate a dryingagent that has been used to dry ethanol, made in the same process thatalso makes distiller's grains.

Referring now to FIG. 4, here is shown a block flow diagram,schematically setting forth variant methods in accordance with otherembodiments of the invention. Both a supplemental feed member 34comprising Powder River Basin coal, and a biomass fermentate separationresidue 35, are supplied to a step of providing 400 a feed. Aspreviously described, the step of “providing” 400 may comprise apretreatment step such as pyrolysis, catalytic conversion, drying,concentrating, and/or charring (not specifically shown here). The stepof providing 400 generates a provided feed 36. The provided feed 36 isthen supplied to a gasifying step 401 in a gasification reactor, toproduce a mixture 37 comprising, CO and H₂. This mixture 37 is supplied(either directly or indirectly) to a contacting step 402 wherein themixture 37 is contacted with a hydrocarbon synthesis catalyst in asynthesis reactor to produce heat 40 and an effluent 38 comprising atleast paraffins. The effluent 38 is then upgraded in a hydroprocessingstep 403 to produce a liquid transportation fuel component 39.

Heat 40 may be supplied to any one or more of six thermal processes 410,shown collectively in a dotted box. Each of the six thermal processesare biomass liquefaction 404, fermentation 405, fermentation productdistillation 406, dehydrating agent regeneration 407, fermentateseparation residue concentrating 408, and fermentate separation residuedrying 409.

As used herein, approximating language may be applied to modify anyquantitative representation that may vary without resulting in a changein the basic function to which it is related. Accordingly, a valuemodified by a term or terms, such as “about” and “substantially,” maynot be limited to the precise value specified, in some cases. Themodifier “about” used in connection with a quantity is inclusive of thestated value and has the meaning dictated by the context (for example,includes the degree of error associated with the measurement of theparticular quantity). “Optional” or “optionally” means that thesubsequently described event or circumstance may or may not occur, orthat the subsequently identified material may or may not be present, andthat the description includes instances where the event or circumstanceoccurs or where the material is present, and instances where the eventor circumstance does not occur or the material is not present. Thesingular forms “a”, “an” and “the” include plural referents unless thecontext clearly dictates otherwise. All ranges disclosed herein areinclusive of the recited endpoint and independently combinable.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Accordingly, theinvention is not to be seen as limited by the foregoing description, butis only limited by the scope of the appended claims.

1. An integrated method for producing fuel from biomass, the methodcomprising the steps of: (a) providing a feed comprising biomassfermentate separation residue, (b) gasifying feed from (a) in agasification reactor to produce a mixture comprising CO and H₂; (c)contacting the mixture comprising CO and H₂ with a hydrocarbon synthesiscatalyst in a synthesis reactor to produce heat and an effluentcomprising a liquid transportation fuel component, and (d) supplying atleast a portion of said heat to at least one thermal process selectedfrom the group consisting of biomass liquefaction, fermentation,fermentation product distillation, dehydrating agent regeneration,fermentate separation residue concentrating, and fermentate separationresidue drying.
 2. The method of claim 1, wherein at least a portion ofsaid heat is supplied to a biomass liquefaction process comprisingenzymatic and/or bacterial decomposition of biomass.
 3. The method ofclaim 1, wherein at least a portion of said heat is supplied to afermentation product distillation process comprising distillation of afermentate to separate an alcohol.
 4. The method of claim 1, wherein atleast a portion of said heat is supplied to a fermentation processcomprising enzymatic, bacterial, and/or yeast-mediated production of analcohol.
 5. The method of claim 1, wherein at least a portion of saidheat is supplied to a dehydrating agent regeneration process comprisingregeneration of a spent solid dehydrating agent.
 6. The method of claim1, wherein at least a portion of said heat is supplied to a fermentateseparation residue concentrating process comprising reducing volume of afermentate separation residue.
 7. The method of claim 1, wherein atleast a portion of said heat is supplied to a fermentate separationresidue drying process comprising removing at least some moisture from afermentate separation residue.
 8. The method of claim 1, wherein atleast a portion of said heat is supplied to at least two of said thermalprocess.
 9. The method of claim 1, wherein at least a portion of saidheat is supplied to at least four of said thermal process.
 10. Themethod of claim 1, wherein said biomass fermentate separation residue isderived from fermentation of at least one plant biomass selected fromthe group consisting of woody materials, forest residues, agriculturalresidues and crops.
 11. The method of claim 1, wherein said biomassfermentate separation residue is at least one corn-based materialselected from distiller's wet grains (DWG), distiller's dry grains(DDG), dried distiller's grains with solubles (DDGS), and corn-basedgrain stillage syrup.
 13. The method of claim 1, wherein said step ofproviding a feed comprises performing one or more treatment selectedfrom the group consisting of pyrolysis, catalytic conversion, drying,concentrating, and charring upon a biomass fermentate separationresidue.
 14. The method of claim 1, further comprising one or more stepof adjusting the CO/H₂ ratio in said mixture comprising CO and H₂ by anadjusting step selected from one or more of: selective removal of CO,selective removal of hydrogen, water-gas shift, andreverse-water-gas-shift.
 15. The method of claim 1, further comprisingan additional step of at least partially removing at least one impurityselected from the (group consisting of CO₂, NH₃, H₂S, HCN, HCl, COS, N₂and Hg from the mixture comprising CO and H₂ prior to contacting saidmixture with the hydrocarbon synthesis catalyst.
 16. The method of claim1, further comprising an additional step of treating at least of portionof said effluent comprising a liquid transportation fuel component by ahydroprocessing, step selected from one or more of hydrocracking,hydrotreating, and isomerization.
 17. The method of claim 1, whereinsaid step of providing a feed comprises mixing biomass fermentateseparation residue with at least one supplemental feed member selectedfrom the group consisting of low rank coal, liquid hydrocarbonaceousfuel, coke, oil shale, tar sands, asphalt, pitch, another biomass-basedmaterial, and mixtures thereof.
 18. The method of claim 1, wherein thegasification reactor is a fixed bed, bubbling bed, fluidized bed, orentrained flow gasifier.
 19. The method of claim 1, wherein said liquidtransportation fuel component is a hydrocarbonaceous fuel having aboiling point within the range of gasoline, jet fuel, kerosene, ordiesel fuel.
 20. The method of claim 19, wherein said liquidtransportation fuel component is an aviation turbine fuel having atleast one characteristic selected from H/C ratio of greater than about1.85, flash point of at least about 38° C., and average freeze point ofless than about −40° C.
 21. An integrated method for producing a turbinefuel from corn-based biomass, the method comprising the steps of: (a)providing a feed comprising corn-based biomass fermentate distillationresidue; (b) gasifying feed from (a) in a gasification reactor toproduce a mixture comprising CO and H₂; (c) contacting the mixturecomprising CO and H₂ with a hydrocarbon synthesis catalyst in asynthesis reactor to produce heat and an effluent comprising a liquidturbine fuel component; and (d) supplying at least a portion of saidheat to at least three thermal processes selected from the groupconsisting of corn liquefaction, corn mash fermentation, cornfermentation product distillation, corn-based ethanol dehydrating agentregeneration, corn mash fermentate distillation residue concentrating,and corn mash fermentate distillation residue drying.
 22. An integratedsystem for producing fuel from biomass, the system comprising, (a) aunit configured to provide a feed comprising biomass fermentateseparation residue; (b) a gasification reactor for gasifying feed from(a) to produce a mixture comprising CO and H₂; (c) catalytic hydrocarbonsynthesis zone configured to react the mixture comprising CO and H₂ toproduce heat and an effluent comprising a liquid transportation fuelcomponent; and (d) at least one heat supply conduit configured to supplyat least a portion of said heat to at least one thermal process selectedfrom the group consisting of biomass liquefaction, fermentation,fermentation product distillation, dehydrating agent regeneration,fermentate separation residue concentrating, and fermentate separationresidue drying.